A computer network is a collection of interconnected computing devices that may exchange data. Computer devices on the computer network may communicate with each other using a system of addresses such as internet protocol (IP) addresses. Some computer devices on the computer network may host web-based services or resources that are available to users such as, for example, a website. A user may not know the individual IP address of a computing device or collection of computing devices hosting a website. However, the user may know the uniform resource locator (URL) for the resource the user would like to reach. The URL may be a more memorable reference such as, for example www.somewebsite.com. When the user enters the address into a browser of a computing device, the computing device may contact a domain name system (DNS) server to resolve the URL into an IP address hosting the resource. Some websites contain content that may be harmful to a receiving computer device such as, for example, a virus. Some websites may contain content that some users may find objectionable.